Ill. Admin. Code tit. 35, § 820.404
c) Trust Agreement
d) Payments into the Trust
2) Pay-in Period
4) First Annual Payment
e) Evaluation by Trustee
g) Release of Excess Funds
h) Reimbursement for Removal Expenses
3) If the Agency determines, based on such information available to it, that the remaining cost of closure will be greater than the value of the trust fund, it must withhold reimbursement of amounts it determines are necessary to preserve the trust corpus to accomplish closure until it determines that the owner or operator is no longer required to maintain financial assurance. If the fund is inadequate to pay all claims after closure is completed, the Agency must pay claims according to the following sequential priorities: